Short-circuiting device



Jan. 6, 1931. v F. Hlss 1,788,194

SHORT CIRCUITING DEVICE Filed June 14.. 1929 l IIIIII4 l l l n ATTO RN SYS '25 modification.

Patented Jan. 6,r 1931 l UNITED STATES HELDER I. Hiss, or SPRTNGEIELD, omo, `AssIeNon 'roRoBBINs & MYERS, v`1Ne.`,go11- SPRINGFIELD, oHIo, A coEPoRATIoNoFoHIo v sHoRT-emcm'riive DEvrcE j Application mea June 111, 1929. serial Np, 2371,015.

This machine relates to short circuiting de vices for electric 'motors and it particularly I relates to thattype of short circuiting device employing a plurality of centrifugally oper- 5 ated weights arranged in an annular series and adapted to make a direct contact kwith the commutator bars. f

The obj ect of my invention is to provide a simple and effective arrangement whereby 10 the weights after Contact with the commutator bars may have an additional slidingA movement on the bars for the purpose of preserving good contact surfaces. A

In the accompanying drawings:

Fig. 1 is a view partly in side elevation and partly in longitudinal section of a short circuiting device embodying my improvements, the short circuiting` elements being in inoperative position. Y v 26 Fig. 2 is a view similar to the sectional portion of Fig. 1 showing theshort circuiting elements in operative position.

Fig. 3 is a section on the line 3 3 of Fig. 1. Fig. 4 is a longitudinal section lshowing a Referring to the drawings, 1 represents the shaft of the motor, 2 the core of the commutator and`3 the commutator bars having their outer ends provided with inclined con- 30 tact surfaces 3. v Slidably mounted upon the motor shaft is a sleeve 4 having fast thereto a cup-shaped' disk 5 within which are mounted the short circuiting elements, each consisting of a plate or slug 6, the outer end of which 35 is provided with a roundedear 7 to form apivot and with a rounded nose 8 to form a ontact point, the bend in the disk serving as a fulcrum fory the weights Vand being rounded `to conform to the rounded formfof theV pivot ears; Theseplates or slugs are arranged -in an kannularseries about the sleeve and are held in their normal inoperative position bv `a ring,

` 7 or washer 9 which is pressed in yielding en-v gagement with the outer edges thereof by'a coil spring 10 which' is confined between the y `ring`9 and awasher fixed against endwise movement on the sleeve 4. f

tor shaft is resisted by a conicalvspira'l spring `to theend of the sleeve 4 and yconfined by-a disk 14' mounted against theV shoulder of collar 15 fixed to the motor shaft.

In operation, `when them'otor has acquired afpredetermined speed,the`weights 6 swing outwardly against "the compression of the spring 10, and make" contact with' thecommutator bars. Increased speed of the motor then'causes a further outward movement of` the weights against thecompressi'on k'of the spring 12, this additional movement causing the contactnnoses 8 to impart the desired wiping action'upon the inclined contact surfaces 1 ofthe commutator bars.` Bythis construction the action of each springis entirely 111-' dependent' of the other and allowsthe weights to first makev contact with the commutator barsrand then havev an additional wiping: movement upon the bars. i c vIn Fig. 4 there is shown a modilication'in the form ofthe springvwhch controls the axially movable sleeve; In this case the spring is a coil spring, as indicated at 16 which is placedfmainly in a large bore or recess 17 in .the sleeve 4 and is confined between the inner wall of the recess and a nut 18 threaded on the motor shaft. e f l i- *In order to prevent'th'e weightsfrom binding, I have divided the series of `weights kclaim 1. In a short circuiting device for electric motors, a shaft, alsleeve'axially movable upon Y said shaft, an annular series of weights VCon-v fined on said sleeve movable ontwardlyby `centrifugal force to contact'with the commutatorbars,aspringon said sleeve opposing the initialmovement of said weights, and a f second spring on said shaft opposing axial movement of said sleeve due to further outward movement of the weights, but which is vineffective to oppose the initialr movement of Axialmovement of the sleeve 4l on the ymoy the weights.

*2. In a short clrcuitingdevice for electric motors, an axiallymovable sleeve arranged on the shaft of the motor, a cup-shaped rotating disk connected with said sleeve, an annular series of Weights on said sleeve having their outer ends fulcrumed on said disk, a springen said sleeve to oppose the initial out- Ward movement of said weights byi centrifugal force, land a Second spring on the shaft of the motor to oppose axial movement of said sleeve due to further outward movement of the weights, but which is ineffective to op pose the initial movement of the weights.

3. In a short circuiting device for electric motors, a motor shaft, a sleeve axially movable thereon, a disk mounted on the outer end of said sleeve having an annular `flange, and an annular series-of Weights about said sleeve, the -outer end of each Weight hav-ing Va projection forming a pivot fuleru-me'd on the outer flanged portion of said disk, .a spring on said sleeve tending to oppose :the initial outward swinging movement of said Weights by centrifugal force, and a ysecond spr'in g learried by said shaft and .bearing oli-said sleeve to oppose axial movement of said. sleeve but permitting the vContact points Vof said Weights to have -a limited lsliding movement upon the commutator bars due to further outward movement of the weights, ibut which is ineffective to oppose the initial movement of the Weights.

4f. In a short ci-rcuiting device for Felectric motors, a shaft, Ia series lvof :commutaftor hars mounted thereon having inclined Contact surfaces, a sleeve axially .movable upon said shaft, a spring zon said'shat hearing against said sleeve, a housing carried by :said sleeve, an annular series of Weights about'said sleeve and having their outer lends tulcrumed on said hou-sing, `Contact .noses also :on Ythe outer ends of said weights adapted when said Weights are 'thrown loutwardly lby cent-ri fugal force to Contact the inclined :surfaces of said commutator hars, a 'spring-0n said 'sleeeve Sto oppose the initial outward movement thereof, said first mentioned spring permitting limited aXial movement o-fsaid'sleeve after -said Weights have made Contact with said vbars due to further outward movement :ofthe weights, but which is ineffective to oppose ithe initial. movement of the Weights.

In testimony whereof I have hereunto set my hand this 27th day of May, :1929.

FIELDER I. HISS. 

